I have built a nix-shell based dev environment for my team at work. It installs fairly quickly on machines as the majority of it is available from the nix binary-cache. There is one package though nixpkgs.beam.packages.erlangR21.elixir_1_7
I wanted to set up a binary cache for that as it takes about 10 minutes to build it from source. I setup nix-serve on my serve and tried copying to it via nix copy and nix-copy-closure. I see that the server has the package in its /nix/store. I setup the nix.conf on the dev machine uninstalled the dev environment and then nix-garbage-collected the machine and tried to rebuild the dev environment. it rebuilt the package rather than grab it from the binary-cache server I set up.
Can anyone give me advice as to how to properly set this up. I want to deploy this to my team of 20 devs and saving 10 minutes a person would really add up.